Fusarium and Verticillium wilt
Soil fungi that block the plant's water pipes, so it wilts even when watered.
What you'll see
- Wilting that often starts on one side or one branch and doesn't recover after watering.
- Lower leaves yellow, then brown, and the plant stays small.
- Brown streaks inside the stem when you cut it lengthwise near the base.
Why it happens
Soil-borne fungi enter through the roots and block the plant's water-carrying tissue. They survive in soil for years.
How to fix it
- There is no cure: pull out infected plants with as much root as possible, and bin them.
- Don't move their soil on tools, boots or pots.
- Trees and shrubs with Verticillium wilt sometimes recover: prune dead wood and keep them watered.
Keep it from coming back
- Choose resistant varieties, such as tomatoes labeled V or F.
- Don't replant susceptible plants in that soil for several years.
- Use healthy transplants and well-drained soil, and don't overwater.
Sources
General guidance, not a diagnosis. For valuable, edible or outdoor crops, check with a local extension service or plant expert. Use any product exactly as its label says, and keep children and pets away while it dries.